This invention concerns an improved catalytic process for producing hydrogen peroxide from hydrogen and oxygen. The process improvements described herein permit production of hydrogen peroxide in concentrations greater than heretofore possible. Furthermore, the generally higher than expected concentrations are achieved in a substantially all-aqueous reaction medium. Thus, process safety is assured and a major impediment to a high-yield, safe process for making hydrogen peroxide is removed.
In regard to the danger inherent in producing hydrogen peroxide in the presence of an organic component, reference is made to the following publications: Swern, "Organic Peroxides", Wiley Interscience, New York, 1970, page 26 (extreme caution); Schumb et al., "Hydrogen Peroxide", Reinhold Publishing Corporation, 1955, page 179 (explosive characteristics); Halle, Chemical and Engineering News, page 4, Nov. 19, 1984 (potential hazard of . . . organic peroxide); Schwoegler, Chemical and Engineering News, page 6, Jan. 7, 1985 (shock sensitivity of acetone peroxides).
There are several publications which appear to ignore the note of caution counseled by the foregoing commentators, including: U.S. Pat. Nos. 4,389,390; 4,379,778; 4,336,238; and 4,336,239. Since explosion hazards are greater at increased concentrations of hydrogen peroxide-in-organic, the relatively low concentrations of hydrogen peroxide heretofore produced by the art may represent an attempt to lessen the risk of explosion.
Processes that do not employ the dangerous expedient of producing mixtures of hydrogen peroxide and an organic component have other features that distinguish them from the process of this invention. For instance, U.S. Pat. No. 4,009,252 discloses a process employing hydrogen pretreatment of a Pd-on-silica catalyst. U.S. Pat. No. 4,279,883 discloses Pd catalysts on various supports all described as equivalent for support purposes.